It is known in the art that certain benzoxazolone derivatives are useful as fungicides and bactericides for agricultural and horticultural purposes. For example, German Patent Specification No. 10 23 627 describes the anti-fungal and anti-bacterial properties of some benzoxazolone derivatives whose benzene ring bears a substituent such as 5-chloro, 5,6- ot 5,7-dichloro or 4,5,7-trichloro group but no alkyl substituent. German Patent Specification No. 11 47 007 discloses the antimicrobial properties of 4,5,6,7-tetrachlorobenzoxazolone, while U.S.S.R. Patent Specification No. 355,008 teaches such properties of 4,5,6-trichlorobenzoxazolene.
Further, Japanese Patent Publication No. 23519/65 describes the fungicidal and bactericidal properties of benzoxazolone derivatives of the formula: ##STR1## wherein R.sub.1 =R.sub.2 =R.sub.3 =H; R.sub.1 =Cl, R.sub.2 =R.sub.3 =H; R.sub.2 =Cl, R.sub.1 =R.sub.3 =H; R.sub.1 =R.sub.2 =Cl, R.sub.3 =H; or R.sub.1 =R.sub.2 =R.sub.3 =Cl; and R.sub.4 is phenyl optionally substituted by halogen, nitro, lower alkyl or lower alkoxy.
We have synthesized and carefully studied a variety of other new benzoxazolone derivatives in an attempt to develop new benzoxazolone microbicides which possess a low toxicity and good safety and exhibit a high activity against a wide range of fungi and bacteria. As a result, we have now discovered new benzoxazolone derivatives which have not been described in literatures and which are very useful as fungicides and bactericides. The derivatives of this invention carry three chlorine substituent at 5-, 6- and 7-positions of the benzene ring. Surprisingly, these 5,6,7-trichlorobenzoxazolone derivatives have been found to possess considerably improved fungicidal and bactericidal properties over those of known 4,5,7-trichlorobenzoxazolone and 4,5,6-trichlorobenzoxazolone as will be clearly seen from Examples hereinafter.
An object of this invention is to provide new benzoxazolone derivatives useful as anti-fungal and antibacterial agents for non-medical utility. Another object of the invention is to provide processes for the preparation of these benzoxazolone derivatives.
Further object of this invention is to provide fungicidal or bactericidal compositions for non-medical uses containing the derivatives as active ingredient. Still further object of the invention is to provide a method of combating fungi and bacteria using the derivatives or the compositions containing them.
Other objects and advantages of this invention will become apparent from the following description.